1、Medical Protozoa,Zhou Huaiyu MD person to animal; vector transfer. 1. Trophozoite （滋養(yǎng)體） is a living stage of protozoa when they can move, take food and reproduce. It is usually the pathogenic stage. 2. Cyst （包囊） is the resting stage of a protozoa with a protective wall. It is usually the infective s

2、tage. Its functions are protection, transmission and multiplication.,. Life cycle,3. Site of inhabitation: digestive tract; urogenital canals; blood and tissues. 4. Infective route: mouth; direct or indirect contact; sexual transmission; placenta; insect sucking blood, blood transfusion and breath.,

3、. Characteristics of Pathogenesis,1. Damage by proliferation (增殖）of protozoa. 2. Damage by diffusion (disperse, 擴(kuò)散) of protozoa. 3. Damage by toxin (毒素)of protozoa. 4. Damage by opportunistic protozoa（機(jī)會致?。? the protozoan living in the human body in commensalisms make the host attack when his immuni

4、ty is lower or restrained, such as Pneumocystis carinii and Toxoplasma gondii.,溶組織內(nèi)阿米巴,Entamoeba histolytica 溶組織內(nèi)阿米巴,E. histolytica （亦稱痢疾阿米巴 ） is the only pathogenic amoeba among all intestinal amoebae. world-wide in distribution, infecting perhaps 10% of worlds population especially in some develop

5、ing countries may cause up to 100,000 deaths each year oral-faecal transmission,.Morphology,Pay attention to stages that have diagnostic value（trophozoite, cyst),1. Trophozoite (active form),(1) Averages 2040 m in diameter. (2) Actively move by Pseudopodium when living. (3) The difference between en

6、doplasm and ectoplasm is distinct. Red blood cell (RBC) can be found. (4) The nucleus, vesicular type, can be clearly seen in the specimen stained with hematoxylin (蘇木素）.,Amoeba feeds on microscopic organisms or cells. When the amoeba encounters a suitable target, the cytoplasm flows round and engul

7、fs it, in a food vacuole. Then endoplasm flows slowly into it. The cytoplasm secretes enzymes into the food vacuole. The enzymes digest the food.,1.1 Electron microscope of trophozoite,Pseudopodium,1.2 Phase contrast photomicrograph of cultured E. histolytica trophozoites,Move by Pseudopodium when l

8、iving : A. broad or finger-like in form B. thrust out quickly, formed with ectoplasm C. then endoplasm flows slowly into it.,Motility is irregular progressive and directional , 5m/s.,Movement of E. histolytica,Nucleus of E. histolytica,*The characteristics of the nucleus of E. histolytica are useful

9、 in differentiation of the pathogenic amoeba from other non-pathogenic amoebae.,Nucleus membrane is delicate but distinct line; Peripheral chromatin granules（核周染粒） are fine and well-distributed on the inner surface of the nuclear membrane.,Karyosome or endosome (核仁 ) is small and centrally located.,

10、1.3 Iron-hematoxylin（鐵蘇木素） stained of Trophozoite,2. Cyst,(1) Immature cyst is spherical in shape, about 10 20 m, and has one or two nuclei. (2) Mature cyst: the shape and size is same as the immature cyst, but it has 4 nuclei.,2. Cyst,(3) The characteristics of the cyst nucleus are similar to that

11、of the trophozoite. (4) The other two morphological features are the glycogen vacuole （糖元泡）and the chromatoid body (or bar) （擬染色體） . The chromatoid bar has two round and smooth ends.,2.1 Electron microscope of cyst,2.2 Hematoxylin stained Immature cyst with 1 nucleus,In the iron-hematoxylin stained

12、specimens the chromatoid body or bar (擬染色體) and nucleus are dark blue in color.,2.2 Hematoxylin stained Immature cyst with 2 nuclei -,The glycogen vacuole (糖原泡) has been dissolved during the process of staining, so it appears as an empty vacuole.,2.2 Hematoxylin stained Mature cyst with 4 nuclei,Cys

13、t with 4 nuclei is infective stage, chromatoid bod and lycogen vacuole not found.,This is a mature cyst and contains four nuclei. However, only two nuclei are visible in this plane of focus, and a chromatoid bar is still present; approximate size = 17 m.,2.2 Hematoxylin stained Mature cyst,2.3 Iodin

14、e stain(碘染) of cyst,The glycogen appears brown in color, but the chromatoid bar can not be stained and has a refractory appearance. Iodine stain for the chronic case or carrier (haemotoxylin stain for teaching),.Life Cycle,1. Infective stage: cyst with 4 nuclei 2. Infective route: mouth 3. Site of i

15、nhabitation: large intestine; liver, lung and other organs（ectopic parasitism） 4. Multiplication: binary fission 5. Pathogenic stage: trophozoite 6. Diagnostic stage: cyst; trophozoites 7. Normal life cycle: cyst-trophozoite-cyst,1.Pathogenic mechanism,Pathogenic factors： (1).Toxicity of parasites p

16、athogenic- nonpathogenic complex. Entamoeba histolytica Entamoeba dispar（迪斯帕內(nèi)阿米巴） (2).Symbiotic bacteria (3).Defence barrier immunity,lectin（凝集素）, amoebic pore forming protein（阿米巴穿孔素）and protein dissolving enzyme（蛋白溶解酶）,III. Pathology,Coloured scanning electron micrograph (SEM) of E. histolytica amo

17、ebae (blue) invading the lining of the large intestine (colon).,Magnification: x1000 at 6x6cm size.,The lectin guides the trophozoite to adhere to the intestinal epithelia, neutrophils and red blood cells. These pathogenic materials destroy the hosts tissues.,1. Pathogenic mechanism,2. Pathogenic ch

18、aracteristics,Pinpoint lesion on mucous membrane. Typical flask-shaped ulcer(燒瓶樣潰瘍). The open of the ulcer toward intestinal lumen looks like a crater.,3. Clinical classification,Asymptomatic infection (carrier) 90% Sympomatic cases 10% 8-10% dysentery, colitis, etc 0.1% deaths,3.1 Intestinal amoebi

19、asis腸阿米巴病,A. Amoebic dysentery: most common form of amoebiasis. The acute case discharges unformed feces with pus and blood several times per day, tenesmus（里急后重） , the pain in right inferior part of the abdomen, nausea, low fever around 38, and fatigue. The jam-like stool with foul smell, in which t

20、here are great number of trophozoites and Charcot-Leyden crystals(夏科-雷登結(jié)晶體),Charcot Leyden Crystal 夏科-雷登氏結(jié)晶體,These diamond shaped crystals are often seen in amoebic dysentery faeces and may also be present in other parasitic infections. They are absent in bacillary dysentery.,b. Chronic amoebic coli

21、tis,It manifests vague abdomen discomfort, alternation of constipation便秘 and diarrhea, stool with mucus and foul smell, nausea, anorexia厭食, fatigues, weight loss.,3.2 Extra-intestinal amoebiasis (腸外阿米巴病),a. Amoebic liver abscess （肝膿腫）,Hepatomegaly and tenderness, hepatic pain becomes more severe and

22、 continuous, high fever, nausea, vomiting, jaundice (icterus), delirium（譫妄）, septic shock, coma, fatalness and mortality (death rate) of 50% . *The most common extra-intestinal amoebiasis is the liver abscess due to the parasite getting into the liver through the portal vein system.,Gross pathology

23、of amebic liver abscess,Tube of chocolate pus from abscess,Gross pathology of amebic liver abscess,Extra-intestinal amoebiasis,c. Pulmonary: chest pain, cough, jam-like sputum, the shadow of the abscess can be seen on X-ray. d. Brain: headache, nausea, vomiting, delirium, coma. e. Other extra-intest

24、inal amoebiasis：Amoebic vaginitis, Amoebic urithritis, Skin fistulas of anus .,. Diagnosis 1. Stool examination, Pay attention to stool examination,(1) Before the patient taking medicine the stool specimen should be collected. (2) The container must be clean and free of salt, acid and alkaline. (3)

25、Trophozoites should be examined soon after they have been passed. (4) keep the specimen warm in order to keep the trophozoites activity. (5) Select the bloody and mucous portion for examination.,Cyst-iodine stain,Notice: Iodine stain for the chronic case or carrier,Other methods,2. Immunological tes

26、t for reference: IHA, IFA, ELISA . 3. X-ray for lung amoebic abscess. 4. Biopsy of rectum and sigmoid by rectoscope直腸鏡 or sigmoidoscope乙狀結(jié)腸鏡. 5. B ultrasonography and Liver puncture for the liver abscess. 6. Computed tomograph ( CT ) and magnetic resonance (MR) for the brain abscess.,An Amoebic Live

27、r Abscess Being Aspirated,Note the reddish brown color of the pus (anchovy-sauce魚子醬). This color is due to the breakdown of liver cells.,.Epidemiology,E.histolitica infection are worldwide distribution but more prevalent in the tropics and subtropics. The high incidence of amoebiasis is due to both

28、natural factors and poor sanitation. The acute case of amoebic dysentery has no significance in transmission of the disease as trophzoites cannot survive long outside the body of the host. The cyst may remain viable in a moist, cold condition for over 12 days, but be killed by drying, by temperature

29、 over 55., . Treatment and Prevention,Treatment: * Metronidazole （甲硝唑，滅滴靈）is recommended for acute amoebic dysentery. Chloroquine （氯喹） is used for treating and preventing liver amoebic abscess. *The compatibility of metronidazole and chloroquine is used for the radical cure of amoebiasis. Paromomyci

30、n(巴龍霉素） , Diodoquin（雙碘喹）for carriers,Prevention,Sanitary disposal of stool. Preventing food, vegetable, fruit and drinking water from the contamination of cyst. Food and drinks must be protected from flies. Pay attention to personal hygienic (finger) and health check of food handler and waiter in th

31、e restaurant.,WORLD TOILET DAY DONT LAUGH, THIS SHiT But IS SERIOUS.,Source from WHO,Entamoeba coli（結(jié)腸內(nèi)阿米巴）,Prevalence in China is estimated at 1.5 %; prevalence in tropics may be up to 100%,1. TROPHOZOITE,20 to 30 m in diameter - granular endoplasm is coarser than E. histolytica - structure of nucleus: _ - lives